On this, and I'm bringing this up now because I've seen a lot of people enter the same picture in more than one contest. If your picture is in more than one contest at a time and wins in one, it will be automatically disqualified from the other. See rule #6
It is allowed, but I recommend that you don't for the above reason. Find another picture that is just as good (or better) and enter that one instead. Then, not only will you not be risking a picture that could be disqualified, but you'll also be using an all-new picture that might not have had a chance yet that could possibly do better. I hope this answers your question.